title: Stress distribution changes after root canal therapy in canine model: a finite element study.
abstract: BACKGROUND
  The fracture strength of endodontically treated teeth compared to vital ones has long been a source of controversy. It is not clear how root canal therapy affects the stress distribution in teeth. The purpose of this study was to evaluate the changes in stress distribution after root canal therapy in a human maxillary canine by finite element analysis (FEM).
  
  
  METHODS
  Two 3D FEM models of a maxillary canine were created; one represented a virgin tooth and the other represented the same tooth after root canal therapy. A single force of 14.1 N was applied 45 degrees to horizontal plane to the center of the palatal surface; stress distribution was then analyzed in both models.
  
  
  RESULTS
  SEQV (VonMises stress) analysis demonstrated an obvious decrease after root canal therapy and the regions near cementoenamel junction (CEJ) showed the highest displacement. The endodontically treated tooth demonstrated higher deflection than the vital one.
  
  
  CONCLUSIONS
  Maximum stress and displacement was repeatedly found in the cervical area, hence more emphasis should be placed on the reinforcement of this region.
authors.affiliation: Department of Orthodontics, Dental School, Dental Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Allahyar
authors.initials: A
authors.lastname: Geramy
authors.forename: Mohammad Jafar
authors.initials: MJ
authors.lastname: Eghbal
authors.forename: Sara
authors.initials: S
authors.lastname: Ehsani
keywords: Finite Element Analysis; Root Canal Therapy; Stress